Circuit breaker



1935 2 Sheets-Sheet l G. R. LNGLEY CIRCUIT BREAKER Filed Dec. l2,

April 20, 1937.

April 20, 1937. G. R. LANG-LEY CIRCUIT BREAKER 2 Sheets-Sheet 2 FiledDec. 12, 1935 mow.

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Patented Apr. 20, 1937 UNITED STATES PATENT OFFICE CIRCUIT BREAKERApplication December l2, i935, Serial No. 54,067 In Canada March 20,1935 Claimsa l My invention relates to circuit breakers, and

J more particularly to circuit breakers of the heavy duty type havingcircuit breaking contacts immersed in an insulating medium such as oil,com- 5 monly used for the interruption of heavy currents at highvoltages, and wherein the arc drawn in breaking the circuit may createpressures within the circuit breaker ranging to a very high order.

-Circuit breakers of the type above referred to have been constructed onthe principle that in order to withstand the high pressures generatedtherein, the walls of the pressure conning conLV talner should approachthe form of a sphere as closely as is practically possible. To this end,

the upper part of the circuit breaker has been made in the form of adome adapted to -be attached to a cylindrical tank, the bottom of whichhas been dished or bulged outwardly to conform tothe generally sphericaloutline.

Too close adherence to the above principle has resulted in excessivelabor costs in the construction of heavy duty circuit breakers. Thedorne shaped top is in itself costly to manufacture, and because of itsshape has increased the diiliculty and cost of locating inserts therein.For example, the-circuit breaker conductor studs which pass through thedome and areI secured thereto, are most readily secured to suitableinserts and the inserts are then welded or otherwise secured in suitableapertures in the dome. 'Ihe locating ci' the apertures, which must bedone with great accuracy, is rendered diiilcult because of the shape ofthe dome, and the welding necessary satisfactorily to secure the insertsin the dome gives y rise to strains within the material of the domewhich at times distort the spacing of the conductor studs. Furthermore,the provision of means for securing the dome shaped top to thecylindrical tank and the provision of a dished-out bottom for the tankadd considerably to the cost of manufacture.

r It is an object of my invention to provide an improved circuit breakerof the type above referred to, capable of interrupting heavy currents athigh voltages and of withstanding the high pressures generated therein,and which will obviate many of the difculties encountered in themanufacture of circuit breakers of the prior art. X It is a furtherobject of my invention to provide a circuit breaker, of the typehavlng'oil ini5 mersed contacts, which will be oil-tight and ex- Aploslon-proof, which will be economical of manui'acture and which willreadily permit the aww rate location of parts.

(Cl. Z-150) It isy a still further object of my invention to provide acircuit breaker construction which lends itself to userin metal cladswitchgear installations now commonly employed in power distributionstations. for which the circuit breakers 5 must be accurately assembledin order to be iri-s terchangeable with other breakers of the same typeand rating in the metal clad installation.

My invention will be more fully/set forth in the following descriptionreferring to the accom- 10 panying drawings, and the features of noveltywhich characterize my invention will be pointed out with particularityin the claims annexed to and forming a part or this specification.

Referring to the drawings, Fig. 1 is a top plan 15 View oi a cire tbreaker embodying my inven tion; Fig. 2 is a view, partly in section, onthe line .A-A of Fig. i; Fig. 3 is a sectional 'view on the line B--B oiFig. l; and Fig. fi is an enlarged isometric view or an operatingelement incorr- 20 porated in the circuit breaker.

In the drawings, Figs. i, 2, and 3, there is shown a circuit breakertank having a top member formed of a hat plate i oi manganese bronze,cold. rolled steel, or other suitable materiali. The plate El whensuitably selected as to thickness will withstand satisfactorilypressures higher than would be encountered during the operation of thecir1J cuit breaker, and at the same time aords a conn siderable savingin rst cost over the dome typt structures heretofore used. At the sametime the plate l may be provided with accurately machined edges to serveas base lines for the location oi parts on the plate i.- Suitableapertures are out in the plate l through which the conductor studs 35 2pass.

Each conductor stud comprises a conducting rod of copper' or similarmetal suitably insulated, preferably with a laminated, impregnatedinsuflating material known to the trade as Herko ,w lite. Each conductorstud 2 is provided at its lower end with a stationary contact structure3 to be later described, and at its upper end the cop:n per rod of eachconductor stud extends beyondl the insulation and may be screw-threadedto per@ 45 mit the ready connection thereto of suitable conrn ductors(not shown), or it may be finished other4 wise, for instance with asilver contact ferrule for plugging intoa socket contact.

Intermediate ithe ends'of eachconductor stud 5@ 2, the insulation may bepartly cut away and a flanged clamping member l formed in two halvessecured about the conductor stud by means of the bolts 5. Each clampingmember i is formed with an axially extending portion S adapted to fit 55snugly within the aperture through which the conductor stud passes, andis also provided with a flange 1 arranged to abut the lower side of.A

plate I and to be secured thereto by the bolts 8. An alternativeconstruction would employ a threaded clamping member arranged to screwinto the top plate.

The stationary contact structure shown comprises contact ngers 9 andbutt contacts I0 which 1o co-operate respectively with wedge shapedportions II and butt contact portions I2 of a movable bridging memberI3. The stationary contact structures 3 are arranged in pairs, each pairbeing bridged by one bridging member I3 and all the bridging members arearranged to be operated between their open and closed circuit positionssimultaneously by means to be later described.

In the structure illustrated, the butt contacts I8 of the stationarycontact structures 3 are biased to their lowermost positions by means ofsprings I4 and are also arranged to move to a lowermost position duringthe circuit opening movement of the bridging member such that any arcingbetween the stationary contact structure -and the bridging member occursbetween the butt contact portions of the respective members. In

this manner, the contact surfaces of the contact y fingers 9 arepreserved for current carrying duty during the circuit closed positionof bridging member I3 and the destruction of the contact surfaces ofiingers 9 by arcing is substantially prevented.

The breaker tank I5 is formed in the regular manner from a piece ofsheet steel rolled into a cylinder and welded at .the edges. Areinforcing and securing band I6 is welded to the outer side of the tankI5 adjacent its upper end'and a fiat bottom I1 is welded to the innerside of the tank I5 adjacent its lower end. The band I6 and iiat bottom'I1 are conveniently and economically made by irst selecting asubstantially rectangular piece of metal plate having the requiredthickness Aand strength, and then cutting from said plate a circularaperture equal in diameter to the outer diameter of the tank I5. 'I'hewidth of the out may be arranged to substantially equal the thickness ofthe steel sheet used in tank I5, and the remaining circular piece ofsteel plate thus is adapted to fit within the lower/ end of tank I5 andis welded thereto to form the bottom thereof. v

The outer contour'of band I6 may be made as shown in Fig. 1, and in theWider corner portions thereof suitable tapped holes are made for thereception therein of bolts I8 extending through the under side of plateI for the reception therein of y the upper edge of tank I and the grooveprovided with a gasket to form an oil and pressure-proof jointwhen thetank I5 is secured to plate I. It will be apparent that the top platelends 'itself readily to the use of a structural steel supporting frame,the plate itself forming the top horizontal frame member. The plate mayalso be extended to' form an economical support for a solenoid or motoroperated mechanism indicated generally at 36.

Each of the bridging members I3 is rigidly secured to the lower end ofan operating rod 20, the upper end of which is secured to a horizontalcross bar 2I. g The operating rods 20 and -the bridging member I3 aremoved in a vertical direction by means of the links 22 pivoted at 23 inan L-shaped bearing member 24 secured to the under side of the plate I.The links 22 are connected plate I and adapted to secure said plate I totank at one end to the cross bar 2I through a sliding ball connection 25and at their other end the links 22 are provided with a cross arm 26arranged to be engaged by the lower end of a plunger 21 operatingthrough registering apertures in plate I and 5 bearing'member 24.

The sliding ball connection, as is shown most clearlyin Fig. 4,comprises a block 28 secured to the cross bar 2I and having ahorizontally extending cylindrical hole or slot 29 and a central verti-10 cal slot 30 therethrough. The end of each of the links 22 is providedwith a circular aperture 3I of a size to receive a steel ball 32therein, and in assembled relation the end of the link operates in theslot 30 and the ball 32 operates in the cylindri- 15 cal hole 29. Thisslidable interlocked connectIon provides for an arcuate motion of theends of links 22 while the cross bar 2I and block 28 move in a verticalstraight line.

The plunger 21 extends through plate I and is 20 connected at its upperend to one end of a link-33, pivoted at 34 in a bearing block 35 on theupper side of plate I. The other end of link 33 may be connected to anysuitable operating mechanism, either manual or electrically operated,mounted 25 conveniently on plate I and indicated generally by therectangle 36. Bearing member 24 is provided with a collar of leather orother suitable material located around plunger 21 so that the plungermoves freely through the collar, but when 30 pressure develops in thetank the collar closes in on the plunger 21 and prevents escape of oil.

The interior of the tank I5 adjacent the contacts of the breaker islined with a layer 31 of insulating material and, in the embodiment ofmy ,35 invention illustrated, an oil blast chamber 38 is providedenclosing all of the stationary contact structures 3 and bridgingmembers I3. The oil blast chamber 38 comprises a topwall 39 and a. sidewall 40, the top Wall 39 having apertures .40 through which theconductor studs 2 and the operating rods 28 pass, and the side wall 4I)being provided with apertures 4I adjacent the end of each bridgingmember I3. 'I'he principle underlying the operation of the oil blastchamber is well.- 45 understood in the art and further discussionthereof is not deemed necessary. In the embodiment shown, an aperture 42is provided in the top wall 39, opening into a cylinder 43 mounted onthe top of the wall 39, and a piston 44 is mounted to 50 slidevertically in the cylinder 43 for a'purpose which will appear more fullyhereinafter. The piston 44 and cylinder 43 have a diameter which isrelatively large compared with the diameter of the operating rods 20 andthe piston 44 is pro- 55 vided with a vertically extending portion 45arranged under certain conditions to co-operate with the cross arm 26 oflink 22.

As is shown most clearly in Figs. 1 and 3, the cross arm 2I andoperating rods 20 secured there- 60 to, are guided for movement in avertical plane by the frame comprising the four rods 46 which aresecured at their lower ends tov the top wall 3l of chamber 38. 'I'herods 46 are arranged in pairs,

one pair at each end of the cross bar 2 I, and cross 65 members 41 areprovided at each end of the cross bar 2I 'and arranged to co-operatewith the rods 46 and 'guide the cross bar between them. Springs 48 arealso provided at the upper ends of 70 rods 46 so arranged that theupward movement of cross bar 2I during the circuit closing operation ofthe circuit breaker compresses them. When the operating mechanismindicated generally at 36 is released, the springs 48 and I4 operate to-75 aovaifis provide an initial impulse in the opening direction to thebridging members I3.

With the foregoing detailed description of the co-operation of parts inthe construction oi the circuit breaker according to my invention, theoperation of the circuit breaker will be readily understood by thoseskilled in the art. Assuming thatthextank I5 is filled with aninsulating fluid,

-.suchlas oil, to a level somewhat higher than the top of the oil blastchamber 38, and that the bridging members I3 are in the circuit openposition illustrated in dotted lines in Fig. 2, the circuitl breaker isclosed by operating the mechanism indicated generally at 36 to depressthe plunger 2 1, thereby, through links 22 and operating rods 20,raising the bridging members I 3 to the position illustrated by fulllines in Fig. 2.. In this position, the wedge-shaped portions lll of thebridging members I3 engage the contact fingers Sand depress the buttcontacts IB against the bias of the springs I4.' In this position also,the cross bar 2l is at its highest position and compresses the springs48.

The circuit breaker is held closed by the operating mechanism showngenerally at 36and may be opened by releasing the operating mechanism,

either manually or in response to a suitable electrical control.

When the operating mechanism 36 is released, the springs 48 and I4immediately apply an impulse in the opening direction to the bridgingmembers I3, and the bridging members I3 very quickly move to theposition illustrated in dotted lines in Figs. 2 and 3. As the buttcontacts I and I2 separate, an arc is drawn, a relatively high pressureis generated within the chamber 38, and a iiow of oil is forced acrossthe arcing contacts and through the apertures (it, thereby minimizingthe arcing and giving rapid circuit interruption.

During the circuit opening operation, the occurrence of a relativelyhigh pressure within the chamber 38 gives rise to a pressuredifferential acting on the operating rods 20 and opposing the openingmovement of the bridging members i3. When the opening impulse impartedby the springs 48 and I4 is exhausted, this piston effect on theoperating rods 20 may result in a tendency toreclose the circuit breakerand in order to overcome this, there is provided the pressure responsivepiston 44 acting-within the cylinder i3 in response to an increase ofpressure within the chamber 38. The upwardly extending portion d of thepiston 44 is arranged, when moved upwardly to abut the cross arm 26 oflinks 22, thus applyinga force in the opening direction tothe links 22over-balancing the piston effect on operating rods 20 and serving tohold the bridging members I3 in fully opened position.

In the operation of oil circuit breakers of the `type above described,it has occasionally occurred that during the circuit opening operationan arc y has struck between the stationary contact structures ofadjacent phases. In the circuit breaker construction of my invention, Iprevent this occurrence by securing to the inner sides of each of thestationary contact structures3 of the outermost phases a ilap 49 (seeFig. 3) of suitable insulating material extending downward somewhatbelow the lowermost portion of the adjacent stationary contactstructure. As is shown most clearly in Fig. 3, these iiaps 49 aresecured to the stationary contact structure by means of the boltsalready provided for Csecuring this structure to the conductor stud. Ihave found that this type of barrier is superior to existing types inthat the presence of this insulating ap 49 substantially eliminates anyinterphase arcing, and, being preferably nonrigid or exible inconstruction, is free from the tendency of a sti barrier to shatter andat the same time is sufiiciently supported so that its flexibility doesnot interfere with the moving parts adjacent.

It should be understood that my invention is not limited to specificdetails of construction and arrangement thereof herein illustrated, andthat changes and modifications may occur to one skilled in the artwithout departing from the spirit of my invention.

"What l claim as new and desire to secure by Letters Patent of theUnited States is:

l. An electric circuit breaker of the liquid-break type comprising acasing including a cylindrical metal portion, a disc-like metal platesecured within one end of said cylindrical portion to form the bottomwall of said casing, a metal reinforcing band, the outer periphery ofwhich is substantially rectangular, secured `to the outer peripheralwall of said cylindrical portion at the opposite end thereof and a datmetal plate forming the cover structure of said casing, said platehaving a circular groove in registry with the upper end of saidcylinder, said plate constituting a unitary support for the completecircuit breaker structure, and means iordetachably securing said plateto diagonal portions of said reinforcing band 2. An electric circuitbreaker of the liquid-break type comprising a metal casing, a flat plateprovided with a lateral `extension forming the cover structure of saidcasing, lead-in conductor studs mounted in and extending through saidcover plate, stationary contacts mounted at the lower ends of saidconductor studs, a movable bridging member coacting with said stationarycontacts and connected to lever structure supported with respect to saidplate within said casing, operating mechanism mounted on said lateralextension exteriorly of said casing, and a plunger connected to saidmechanism and guided for vertical reciprocal movement in said plate forengaging within said casing said lever structure.

3. An electric circuit breaker of the liquidbreak type comprising acasing, a flat metal plate having a lateral extension forming the coverstructure of said casing, lead-in conductor studs mounted inandextending through said casing, stationary contacts mounted at the lowerends of said studs, a movable coacting bridging member operable througha lift-rod to closed and open circuit positions, a lever pivotallysupported in depending relation to said plate, said lever operativelyconnected at one end to said lift-rod and provided at its other end witha roller, an operating mechanism mounted on the lateral extension ofsaid cover plate exteriorly of said casing, a plunger connected to saidmechanism guided in said plate for vertical reciprocal movement forengaging said roller and an antireclosing device in said casingincluding a piston adapted to engage said roller.

4. In an electric circuit breaker including relal lll transmittingstraight line movement theretd comprising a member having a longitudinalslot and a coacting member slidable in and interlocked with respect tosaid slot, one of said members being pivotally mounted so that the otherbridging members, and means for preventing member can be. restrained forrectilinear moveinterphase short circuits between the stationary 'nient.contacts of separate phases comprising ilexible 5. An electric polyphasecircuit breaker of the insulating aps secured to the stationary contact5 liquid-break type comprising a casing, a pluralstructure and extendingto the lower extremities 5 ity of pairs of stationary phase contactsmounted of said stationary contact structure. in s aid casing, aplurality of movable coacting GORDON R. LANGLEY.

